Wastegate question

airtroop01

airtroop01

Active member
I have a turbosmart wastegate.
There's a top port and a bottom port. I have a port in the plenum going to the bottom port. The top port is just venting to atmosphere right now. Should this go somewhere? Should I cap it off? Should I leave it as is?

All the directions really say is the top port helps close the waste gate when pressure is added to it. While the bottom port opens the wastegate.

Thanks in advance...
 
you should have gotten a lil fitting to go in there and you'll need to tap into your vaccuum line i believe. let me find my diagram of how they recommend it being plumbed.
 
Your boost controller needs to be in line with the top port.

If you run the top port vented to atmosphere you should be boosting to just the wastegate spring's capability.

Its best to use the fitting thats on your compressor housing for that signal.
 
Frank5L said:
Your boost controller needs to be in line with the top port.

If you run the top port vented to atmosphere you should be boosting to just the wastegate spring's capability.

Its best to use the fitting thats on your compressor housing for that signal.
Click to expand...

Thing is their instructions do not show it that way. They show the top port open and the bottom port going to the boost controller.

Phil,

Did you try turning the boost up with the boost controller? The wastegate has 17# springs in it and that's what you're getting. The controller is turned completely down to not add any additional boost.

Jody
 
I didn't turn the boost up yet... 17 psi is good enough for now. It just seemed strange to let the port vent to atmosphere as per the directions show.
 
that port is not venting anything... there is just nothing pulling on that side of the diaphram inside
 
Depends on the kind of boost controller. If you're not using a controller, then you'll just plug into the side port, which will allow boost pressure to push on the bottom of the diaphragm. This lifts the valve in the gate to bypass the turbine and manage the boost level. If you cap the top port, you create a deadhead and the wastegate won't open.

Some boost controllers manage the "bleed" to the side (bottom) port to control when the gate opens. The controller will effectively block boost to the bottom port until the boost reaches some predetermined level.

Other controllers use a return feed to the top port to effectively increase the spring rate (this is what mine does). So, for instance, you have a 17 lb spring, you have a controller set to feed 3 lbs back to the top of the gate. This makes the effective spring rate 20 lb.

I have just a piddly 6 lb spring in my wastegate, and then do all the boost control above that with the controller.

So, if you're not using a controller that feeds back to the top of the diaphragm, that port needs to stay vented to atmosphere.
 
Also if you just use the bottom port the boost will be very lazy. The waste gate (depending on spring pressure) will want to open early. I would get an electronic control asap.

Dale
 
Bad as L said:
I would get an electronic control asap.
Click to expand...

Steve's right! You're good at spending other people's money!

I'm just single-porting on the big block. Compressor regulator valve on the small block. ;)
 
^ it really depends... fuzzy logic boost controllers are all the rave, but some still create some pretty nasty boost spikes. I read an article a coule of years ago about the comparison of EBC's to MBC's, they concluded that the MBC's were far superior in actually limiting boost spikes as compared to EBC's. they said that a simple ball bearing MBC is the best value, and produced the least amount of boost spikeage. if you're going for an EBC, it's a safe bet to go with Greddy, the HKS EVC had the worst boost spikes (5psi on open throttle).
 
Bad as L said:
Also if you just use the bottom port the boost will be very lazy. The waste gate (depending on spring pressure) will want to open early. I would get an electronic control asap.

Dale
Click to expand...

That's exactly what I was troubleshooting - the boost coming in lazy as well as what seemed like a vacuum leak. However, looking under the hood today, I noticed that I blew off the two thin hoses that go into the aluminum block from the exhaust (maybe dpde unit). So once I reconnected it, the boost came in much quicker... and I hit 20 psi... despite the wastegate just having 17 psi of springs in it.... and then blew the stupid lines off again.

So, boost creep is still prevalent on mechanical wastegate as is on a 'fuzzy logic' boost controller. I think I want to get a electronic boost controller pretty soon. Just waiting til after christmas. Maybe Santa will get me one. :D

The other thing I've been fighting is the blow off valve. I think its pushing air in and causing turbulence at the maf and causing my truck to go way rich then way lean and die.
 
FMOS Racing said:
Steve's right! You're good at spending other people's money!

I'm just single-porting on the big block. Compressor regulator valve on the small block. ;)
Click to expand...

Steve called and woke my lazy *** up this morning.....Why???? he wanted me to talk him into spending more money :D

Dale
 
airtroop01 said:
That's exactly what I was troubleshooting - the boost coming in lazy as well as what seemed like a vacuum leak. However, looking under the hood today, I noticed that I blew off the two thin hoses that go into the aluminum block from the exhaust (maybe dpde unit). So once I reconnected it, the boost came in much quicker... and I hit 20 psi... despite the wastegate just having 17 psi of springs in it.... and then blew the stupid lines off again.

So, boost creep is still prevalent on mechanical wastegate as is on a 'fuzzy logic' boost controller. I think I want to get a electronic boost controller pretty soon. Just waiting til after christmas. Maybe Santa will get me one. :D

The other thing I've been fighting is the blow off valve. I think its pushing air in and causing turbulence at the maf and causing my truck to go way rich then way lean and die.
Click to expand...

One of the first things you have to do is make sure you have enough waste gate....the reason I say this is your remark about boost creep. If the waste gate cant do its job hooked up the way it is then an electronic control wont fix it.

Can't help with the BOV, I have no experience with them and I probably never will :D
Dale
 
Bad as L said:
Steve called and woke my lazy *** up this morning.....Why???? he wanted me to talk him into spending more money :D

Dale
Click to expand...

PM me your number, sometimes I just need to talk as well... HAHAHA
 
Phil, creep and spike are different. Spike is when the boost overshoots your desired amount when the controller feeds in, creep is boost getting higher and higher beyond what the wastegate is set for as RPMs increase.

You'll note in your installation thread that I mentioned that the design of the wastegate piping may be a problem... I'm going to stand by that if you're having creep issues. I don't think that double-perpendicular-to-the-flow wastegate path is going to be adequate at your power level.
 
airtroop01 said:
So once I reconnected it, the boost came in much quicker... and I hit 20 psi... despite the wastegate just having 17 psi of springs in it.... and then blew the stupid lines off again.

So, boost creep is still prevalent on mechanical wastegate as is on a 'fuzzy logic' boost controller.
Click to expand...

:confused:

I was tracking off of what he said there, assuming it was indeed creep.
 
FMOS Racing said:
:confused:

I was tracking off of what he said there, assuming it was indeed creep.
Click to expand...

I totally get where you're coming from. It's just that as far as I know he hasn't done any full throttle runs for more than a second or two max, so he doesn't know yet if the boost is going to creep up yet. Different engine loads may make different boosts at part throttle and I think that's what he's seeing. His BA2400 MAF was maxed immediately in low gear when he did get into it with me, so until he gets the extender set up he shouldn't be doing a bunch of wot datalogs.

Jody
 
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